Bulldozer



March 31, 1970 J, R, SMlTH ET AL 3,503,457

BULLDOZER 2 Sheets-Sheet l Filed Dec. 14. 1967 2 nlM FIG. I

FIG. 2

INVENTORS JAMES R. SMITH HARRY A. LAND ATTORNEY March 31, 1970 J. R.SMITH ET Al- 3,503,457

BULLDOZER Filed Dec. 14, 1967 2 Sheets-Sheet 2 FIG. 3

INVENTORS JAMES R. SMITH 8| HARRY A. LAND BY/VJM 7%;7

United States Patent Ov 3,503,457 BULLDOZER James Richard Smith, LaMotte, Iowa, and Harry Albert Land, Algonquin, lll., assignors to Deere& Company, Moline, Ill., a corporation of Delaware Filed Dec. 14, 1967,Ser. No. 690,649 Int. Cl. E02f 3/ 7 6 U.S. Cl. 172-,8113 7 ClaimsABSTRACT F THE DISCLOSURE A bulldozer including a blade, a pair ofparallel push arms supported at their rear ends on a tractor and havingtheir forward ends connected to the blade; a pair of struts supported onthe respective arms and extending upwardly and forwardly from the armsto and for connection with the back of the blade, at least one of thestruts being extensible and retractable for effecting tilting of theblade; a pair of elongated rigid brace elements having outer endsconnected to the respective arms and extending inwardly and forwardlytoward the center of the blade; a coupler device pivotally supported onthe rear side of the blade and in a central location thereof; and a pairof connectors on the coupler spaced radially from the pivot on oppositesides of the pivot and adapted for connection to the inner ends of thebraces whereby the forces exerted by one of the braces will be forwardlyof the pivot and the lines of force exerted by the other of the braceswill be rearwardly of the pivot.

BACKGROUND OF THE INVENTION This invention relates to a bulldozer andmore particularly to the strut and brace arrangement between the pusharms of the bulldozer and the blade.

The conventional type of bulldozer utilizes a pair of push arms that areconnected to opposite ends of a bulldozer blade. Extending upwardly fromthe upper side of each of the arms is a strut that braces the bulldozerblade and normally at least one of these struts is extensible andretractable for tilting the blade from one end to the other. Alsoprovided are a pair of braces that extend inwardly from the inner sidesof their respective arms and are connected to the center portion of theblade. Heretofore it has only been conventional to strengthen the strutsand braces in accordance with the size of the blade and the size of thetractor that the bulldozer was to be mounted. In testing the bulldozer,should a failure occur in the arms, braces, or struts, the normalprocedure was to enlarge or strengthen the part that failed.

The very nature of the construction of a bulldozer iS such that when theextensible and retractable strut is moved, it places a very strong loadon the push arms since there is a load applied on the arms due to thetilting of the blade which tends to distort or deform the arms. Alsowhen a load is applied to only one end of the blade there is a furthertendency to distort the arms, braces and struts. These are the forcesthat normally create breakage or warping of various of the parts of abulldozer.

SUMMARY OF THE INVENTION With the above in mind, it is the purpose ofthe present invention to provide a bulldozer utilizing a coupler deviceon the rear center portion of the blade that interconnects the innerends of the braces to utilize the force created in each of the braces,as created due to the aforementioned loads, to counteract identicalforces in each of the opposite braces. Specifically it is proposed toprovide a coupler that is carried on the rear portion of the blade so asto swivel about a vertical axis and to provide connectors radiallyspaced from the vertical axis that connect 3,503,457 Patented Mar. 31,1970 to the inner ends of the braces and maintain the lines of force ofone of the braces forwardly of the axis and the lines of force exertedby the other of the braces rearwardly of the pivot.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERREDEMBODIMENT The bulldozer is adapted to be supported on a tractor, shownin dotted representation at 10, and preferably 0f the type of tractorhaving a pair of tracks also shown in dotted representation at 11 and12. The bulldozer is com posed of a pair of push beams 13, 14 adapted tobe disposed on the outer sides of the tracks 11, 12 and supportedthereon by transverse horizontal shafts 15, 16, the latter having attheir outer ends the ball portions 17, 18 of conventional ball andsocket joints. The rear ends of the beams 13, 14 are carried on the ballportions 17, 18 by detachable sockets 19, 20.

The bulldozer blade 25 is provided at the forward ends of the push beams13, 14. The bulldozer blade includes a forwardly disposed arcuate bladeportion 26 with a lower cutting blade 27 continuing downwardly from thelower edge of the blade portion 26. A pair of upright structural plates28, 29 are lixed to opposite ends of the blade portion 26. Welded to theinner faces of the plates 28, 29 and to the rear face of the bladeportion 26 are a pair of vertically spaced horizontal channels 30, 31that serve to brace and reinforce the entire blade. The upper channel 30has at its opposite ends rearwardly extending bracket structure.

Extending rearwardly and fixed to the upper channel are a pair of blocks32, 33, both of which have cavities for receiving a ball portion 34, 35of a pair of end struts 36, 37. The lefthand strut 36 is composed of ahydraulic cylinder 38 and a rod 39, the latter having the ball 34 at itsend. The cylinder is pivotally mounted at 40` to up right brackets 41projecting from the upper surface of the push arm 13. The right strut 37is of a turnscrew type that has its forward end 35 fixed in the block 33by a suitable clamp 42 and its rear end pivotally mounted at 43 toupright brackets 44 welded to the upper surface of the right push beam14. The piston rod 39 and the ball 34 thereon are held in the block 32by a connecting plate 45 bolted into the block 32.

The forward ends of the push beams are connected to the lower outer endsof the blade structure 25 by means of ball and socket joints 49, 50respectively.

Fixed to the rear surface of the main blade portion 26 and centrally inrespect to the fore-and-aft center line of the tractor and bulldozerblade is a rearwardly projecting bracket structure 51 that includes aforward `arcuate shaped section 52 welded to the rear surface of theblade portion 26 and an integral upper horizontal plate portion 53 thatprojects rearwardly. The bracket structure 51 also includes a lowerhorizontal plate 54 positioned beneath the upper plate 53. Extendingbetween the two plates 53, 54 and lixed thereto is an upright pin member55 with a centrally located ball portion 56 that serves as a pivotaljoint for a coupling device indicated in its entirety by the referencenumeral 57.

lWelded to the inner sides of the push beams 13, 14 are a pair of blocks60, 61 having hollow recesses sei-ving as sockets for receiving theball-shaped ends, such as is shown in dotted representation at 62 inFIG. 3, of a pair of converging braces 63, 64. The braces 63, 64 havetheir adjacent inner ends connected to the coupling device 57.

The coupling device 57 is a three-point lever structure composed ofupper and lower bell crank levers 65, 66, each having one arm 67extending rearwardly of the pin 55 and an arm 68 extending slightlyforwardly of the pin 55. As shown in FIGURE 1, the arms aresubstantially 120 degrees apart. The levers 65, 66 have enlarged centralportions with hollowed cone-shaped sections 69, 70 respectively andadjacent socket or partial spherical sections 71, 72 that engage thesurface of the ball portion 56. The two levers 65, 66 are held togetherby a pair of bolts 73, 74 that extend through the outer ends of' therespective arms 67, 68 and operate as connecting elements for the innerends of the braces 63, 64. The nuts on the bolts 73, 74 are equallytightened and rigidly hold the two plates 65, 66 in a relatively tightpivotal connection on the ball 56.

Referring to FIG. l, it will be noted that the braces 63, 64 divergefrom the coupling 57. Also, the brace 63 will exert a force lying in aline whose extension would be rearwardly of the pivot pin 55 and thebrace 64 will exert forces lying in a line whose extension is forwardlyof the pivot pin 55. This feature becomes important for it tends tobalance forces which would normally tend to rack the bulldozerstructure. For example, if a force were to be applied to one end of thebulldozer and in a direction transverse relative to the tractor, itwould tend to create a tensile force in the brace 63 and a compressionforce in the brace 64. The tensile force in the brace 63 would tend todrive the lever 65 in a counterclockwise direction and the compressionforce in the brace 64 would tend to drive the lever 65 in a clockwisedirection. Consequently the two forces in the braces 63, 64 would tendto counteract one another. Consequently the resultant loads or forces onthe respective beams 13, 14 are equalizied. Further, upon extension ofthe hydraulic cylinder or strut 36, there will be created compressionforces in both braces 63, 64. Due to the rocking of the lever 67 on theball 56, the entire coupling device 57 will be permitted to rotateslightly to eliminate the resultant forces on the push arms 13, 14. Thiswill, of course, minimize the tendency of the braces 63, 64 to distortor lbend the arms 13, 14.

What is claimed is:

1. A bulldozer having a blade, a pair of parallel push arms adapted forsupport at one of their ends on a tractor and at their opposite ends forconnection to the blade; a pair of struts supported on the respectivearms and extending n a forward vertical angular relation therefrom to`and for connection with the back of the blade, at least one of thestruts being extensible and retractable for effecting tilting of theblade; a coupler including a vertical pivot portion supported on theback of the central portion of the blade; a pair of elongated rigidbrace elements having and the other brace extending forwardly andinwardly along a line extending rearwardly of the pivot portion; and apair of connectors offset radially and on opposite 4 sides of the pivotportion and adapted for connection to the respective inner ends of thebrace elements whereby the line of force exerted by one brace will beforwardly of the pivot portion and the line of force exerted by theother brace will be rearwardly of the pivot portion.

2. The structure as set forth in claim 1 in which the pivot portion ofthe coupler is a member mounted on the back of the blade with a ballportion of a ball and socket joint being rigid therewith and theconnectors are supported on the ball portion by a centrally locatedsocket that swivels on the ball portion.

3. The structure as set forth in claim 2 in which the socket is formedby a pair of parallel upper and lower bell crank shaped plates with thecenter portions thereof having upper and lower socket portionsrespectively and the connectors are threadedly adjustable pins extendingthrough the opposite ends of the plates and the respective inner ends ofthe braces.

4. The structure as set forth in claim 1 in which the connectors aresubstantially apart.

5. In a bulldozer having a blade and a pair of push arms, theimprovement residing in a three-point lever supported adjacent thecenter portion of the blade to swing laterally on a substantiallyvertical pivot means and including a pair of arms extending fromopposite sides of the pivot means; a pair of elongated rigid braceshaving outer ends connected to the respective arms and extendingforwardly and inwardly to inner ends adjacent the respective arms, withone brace extending forwardly and inwardly along a line extendingforwardly of the pivot means and the other brace extending forwardly andinwardly along a line extending rearwardly of the pivot means; andconnecting means between the respective arms and the inner ends of thebraces whereby the line of force exerted by one brace will be forwardlyof the pivot means and the line of force exerted by the other brace willbe rearwardly of the pivot means.

6. The structure as set forth in claim S in which the pivot means isformed by a ball and socket joint between the lever and blade, and theconnecting means includes pivot pins extending between the arms andinner ends of the braces.

7. The structure as set forth in claim 5 in which the lever is a bellcrank and is carried on the pivot means to articulate laterally and thearms are horiontally disposed so that the respective connecting meansare forwardly and rearwardly respectively of the pivot means.

References Cited UNITED STATES PATENTS 2,943,407 7/ 1960 Long 172-8043,049,820 8/1962 Lichti 172-803 3,187,448 -6/1965 Kolinger 172-8033,234,670 2/1966 Fryer et al. 172-803 3,395,764 8/1968 Wirt 172-803FOREIGN PATENTS 931,067 7/1963 Great Britain.

ROBERT E. BAGWILL, Primary Examiner ALAN E. KOPECKI, Assistant Examiner

